Mitt Romney’s official campaign slogan is “Believe in America.” But unofficially, at least for the primaries, it might as well be “Divide and Conquer.”

On the eve of the next round of nominating contests – Tuesday’s primaries in Alabama and Mississippi and caucuses in Hawaii – that’s the name of the game for the Republican presidential frontrunner.

And as long as both Rick Santorum and Newt Gingrich remain in the race, dividing the “not-Romney” vote, the former Massachusetts governor is well-positioned to build on his lead in the delegate count and head into the Tampa party convention in August with the most delegates, if not the majority.

Polls of Republican voters in Alabama and Mississippi show a three-way dead heat. But the stakes for each candidate are distinctly different. Former Speaker Gingrich must win at least one of the two, or face serious questions about his rationale for staying in the race, analysts say. As a former longtime congressman from Georgia, the South is his home turf. The only two contests he has won are South Carolina and Georgia, and if his campaign is to rebound once again, Alabama and Mississippi are as likely venues as any.

Former Senator Santorum, a champion of social conservatism, also has some purchase in the South, despite his Pennsylvania roots. He won the Super Tuesday primary in Tennessee, and a victory in Alabama and/or Mississippi would show that his appeal ranges further into the South.

For Mr. Romney, the March 13 contests have more upside than down. He’s already expected to win the Hawaii caucuses, and if he can also eke out a victory in even one of the Southern primaries, that would be a coup. The very Northern Romney has tried to connect with voters in Mississippi and Alabama with a little self-deprecating humor – working “y’all” into his patter and talking about “cheesy grits” – but, as in other states, his best argument may still be that he fares best against President Obama in polls.

“It’s likely to be a long night,” says Ford O’Connell, a Republican strategist who has worked on campaigns in the South. “If Romney wins one, this could wind down. If he wins both that might be just short of historic.”

Gingrich maintains that he will stay in the race all the way to Tampa, no matter what. Of course, most politicians insist they’ll never drop out until they do, but few can match Gingrich for self-confidence – especially as long as he has the backing of Las Vegas casino magnate Sheldon Adelson, who has poured millions into a pro-Gingrich super-PAC.

In the delegate hunt, Gingrich is third with 107 behind Romney (454) and Santorum (217), out of 1,144 needed to secure the nomination, according to the Associated Press. The fourth Republican still in the race, Rep. Ron Paul of Texas, has 47 delegates. His continued presence in the race chops up the vote further, though there’s not much call for the libertarian Congressman Paul to drop out. His followers are particularly devoted to him and his unorthodox views, making it likely that many would simply not vote were he not in the race.

On NBC’s “Meet the Press” Sunday, Santorum didn’t call on Gingrich to drop out, but he made clear that’s what he wants.

“The speaker can stay in as long as he wants,” Santorum said, “but I think the better opportunity to make sure that we nominate a conservative is to give us an opportunity to go head-to-head with Governor Romney at some point, and hopefully that will occur sooner rather than later.”

On Monday, all three candidates put in appearances in at least one of the Tuesday primary states, and sought to lower expectations. Speaking on Fox News, Romney said “absolutely not” when asked if he needed to win one of the Southern primaries. He pointed out that John McCain, the GOP nominee in 2008, did not win the primaries in either Alabama or Mississippi.

After a speech to an energy summit in Biloxi, Miss., Santorum told reporters that his rivals had spent more time and money in the two Southern primary states than he has.

“It's very tough,” Santorum said, according to National Journal. “It's basically a one-week campaign. The other campaigns have been here running ads longer than we have and have been spending time here before we did.”

Celebrities have also been pitching in during the final frenzy before Tuesday’s vote. Comedian Jeff “You might be a redneck” Foxworthy stumped for Romney, and actor Chuck Norris made robo-calls for Gingrich.